I was attack last night and he let behind debris of creating a moon of 9 % (can see this in the attack report) and like in a miracle it’s all gone, somebody just recycle it.
Is this normal?
This is not the first time when my debris it’s gone.
How I must create a moon when my debris it’s stolen?

I think you really need to look in the players guide "Moon" section. There are only 50+ threads explaining this. You just have to pick one.